动物3种DNA病毒在宿主细胞内形态发生比较

对猪细小病毒(PPV)、牛疱疹病毒2型(BHV2)和犬腺病毒1型(CAV1)3种动物DNA病毒在宿主细胞内的增殖、释放方式以及所致细胞结构的变化,通过电镜进行了观察比较.(1)这3种动物DNA病毒的复制和装配过程均发生在细胞核内,以毒浆结构(Viroplast)或核内包涵体为增殖场所和物质基础,但并非都形成结晶样结构.(2)有囊膜的BHV2,其核壳体在细胞核内装配完成后,从核内膜上以出芽方式获得囊膜,然后进入核周池,聚集的病毒使核外膜向胞质方向隆起,形成病毒性包涵体而脱离核外膜,并逐渐向细胞膜的方向移动,最后从细胞膜的破损处以病毒包涵体形式释放到细胞间隙.而无囊膜的CAV1,核壳体在细胞核内装配完成后,从细胞核膜破损处或细胞核崩解后进入细胞质,待整个细胞崩解后才能释放出来.无囊膜的PPV,在核壳体装配完成后,成堆地以病毒流的方式,从扩张的核孔释放到细胞质中,待细胞崩解后再释放出来.(3)3种病毒增殖时,宿主细胞的固有细胞器,如线粒体、内质网以及溶酶体等均出现不同程度的超微结构变化,并能诱导宿主细胞出现一些新的结构,除毒浆结构外,还有管状结构、细纤维样结构、周期性结构和髓膜样结构等,其中周期性结构仅见于BHV2感染.

Comparison of the Morphogenesis of 3 Species of Animal DNA Viruses in Host Cells

The modes of replication and egress of 3 species of animal DNA viruses (porcine parvovirus, bovid herpesvirus 2 and canine adenovirus 1) in various host cells and by which the alterations of cellular structure induced were comparatively observed under electron microscope. The results are: (1) The replication and assembly processes of these viruses take place in the nucleus , they make use of the viroplast or nuclear inclusion bodies as multiplication sites and material sources, but not all these viruses can form the crystalline structure. (2) In enveloped BHV2, after the assembly of nucleocapsids, the envelopes are added by budding and then they enter per-inuclear cisternae. The virus particles accumulate and cause the exonuclear membrane to exalt to the cytoplasm, thus forming the viral inclusion bodies which leave the exonuclear membrane, and migrate gradually to cytoplasmic membrane, finally they are released through the leakages of cytoplasmic membrane into the intercellular spaces. In nonenveloped CAV1, after assembly of nucleocapsids in nucleus, the virus particles enter the cytoplasm through the leakages of nuclear membrane or after break down nucleus, and are released after rupture of the damaged cell. The nonenveloped PPV, after the assembly of nucleocapsids in nucleus is complete, the virions flow abundantly into the cytoplasm through the dilated pores of nuclear membrane and are released after rupture of affected cell. (3) When the virus multiplicated in host cells, the organdies such as mitochondria, endoplasmic reticula and lysosomes appeared the substructural alterations of varying extents. These viruses can also induce the affected cell to form some new structures such as tubiform structure, fine fibriform structure, periodic structure and marrow membrane structure, etc. in addition to the viroplast. But the periodic structure is only found in BHV2 infection.